diff --git a/math/matrix/inc/TVectorT.h b/math/matrix/inc/TVectorT.h
index d5573b21b1e44..7f3d482725343 100644
--- a/math/matrix/inc/TVectorT.h
+++ b/math/matrix/inc/TVectorT.h
@@ -72,7 +72,7 @@ template<class Element> class TVectorT : public TObject {
       *this = another;
    }
 #ifndef __CINT__
-   TVectorT(Int_t lwb,Int_t upb,Element iv1, ...);
+   TVectorT(Int_t lwb,Int_t upb,Double_t iv1, ...);
 #endif
    virtual ~TVectorT() { Clear(); }
 
diff --git a/math/matrix/src/TVectorT.cxx b/math/matrix/src/TVectorT.cxx
index 5bbfbc5efd1d3..f6868c619feca 100644
--- a/math/matrix/src/TVectorT.cxx
+++ b/math/matrix/src/TVectorT.cxx
@@ -260,7 +260,7 @@ TVectorT<Element>::TVectorT(const TMatrixTDiag_const<Element> &md) : TObject()
 /// TVectorT foo(1,3,0.0,1.0,1.5,"END");
 
 template<class Element>
-TVectorT<Element>::TVectorT(Int_t lwb,Int_t upb,Element iv1, ...)
+TVectorT<Element>::TVectorT(Int_t lwb,Int_t upb,Double_t iv1, ...)
 {
    if (upb < lwb) {
       Error("TVectorT(Int_t, Int_t, ...)","upb(%d) < lwb(%d)",upb,lwb);